如何通过Wifi P2P将多个客户端连接到一台主机

Question

我正在尝试创建一个WiFiP2P以与2部android手机和1台Raspberry Pi进行通信。我希望一部电话作为主机，第二部电话+ Raspberry Pi作为客户端。

直到知道我可以创建一个测试APP即可通过Wifi直接连接两部手机（测试成功）。我正在关注有关YouTube Wifi P2P的精彩教程。不幸的是，该教程仅显示了如何将一台主机与一个客户端而不是多个客户端连接。 我试图跟随Android开发者guide，但是我没有足够的经验来理解所有内容。 希望你们能帮助我了解我在代码中必须进行的更改并向我解释原因。

以下代码是上述教程的确切副本。

这是我的MainActivity：

package com.example.wifip2p;

import android.Manifest;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.net.wifi.WifiManager;
import android.net.wifi.p2p.WifiP2pConfig;
import android.net.wifi.p2p.WifiP2pDevice;
import android.net.wifi.p2p.WifiP2pDeviceList;
import android.net.wifi.p2p.WifiP2pGroup;
import android.net.wifi.p2p.WifiP2pInfo;
import android.net.wifi.p2p.WifiP2pManager;
import android.os.Handler;
import android.os.Message;
import android.os.StrictMode;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    Button btnOnOff, btnDiscover, btnSend;
    ListView listView;
    TextView read_msg_box, connectionStatus;
    EditText writeMsg;

    WifiManager wifiManager;

    WifiP2pManager mManager;
    WifiP2pManager.Channel mChannel;

    BroadcastReceiver mReceiver;
    IntentFilter mIntentFilter;

    List<WifiP2pDevice> peers = new ArrayList<WifiP2pDevice>();
    String[] deviceNameArray;
    WifiP2pDevice[] deviceArray;

    static final int MESSAGE_READ=1;

    ServerClass serverClass;
    ClientClass clientClass;
    SendReceive sendReceive;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);


        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {
            // Permission is not granted
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.ACCESS_COARSE_LOCATION},
                    1);
        }

        initialWork();
        exqListener();
    }

    Handler handler = new Handler(new Handler.Callback() {
        @Override
        public boolean handleMessage(Message msg) {
            switch (msg.what){
                case MESSAGE_READ:
                    byte[] readBuff = (byte[])msg.obj;
                    String tempMsg = new String(readBuff,0,msg.arg1);
                    read_msg_box.setText(tempMsg);
                    break;
            }
            return true;
        }
    });

    private void exqListener() {
        btnOnOff.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if(wifiManager.isWifiEnabled()){
                    wifiManager.setWifiEnabled(false);
                    btnOnOff.setText("ON");
                    if(mManager!=null) {
                        mManager.removeGroup(mChannel, null);
                    }

                }else{
                    wifiManager.setWifiEnabled(true);
                    btnOnOff.setText("OFF");
                }
            }
        });

        btnDiscover.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mManager.discoverPeers(mChannel, new WifiP2pManager.ActionListener() {
                    @Override
                    public void onSuccess() {
                        connectionStatus.setText("Discovery Started");
                    }

                    @Override
                    public void onFailure(int reason) {
                        connectionStatus.setText("Discovery Starting Failed");
                    }
                });
            }
        });
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int i, long l) {
                final WifiP2pDevice device = deviceArray[i];
                WifiP2pConfig config = new WifiP2pConfig();
                config.deviceAddress = device.deviceAddress;



               mManager.connect(mChannel, config, new WifiP2pManager.ActionListener() {
                    @Override
                    public void onSuccess() {
                        Toast.makeText(getApplicationContext(),"Connected to " + device.deviceName, Toast.LENGTH_LONG).show();
                    }

                    @Override
                    public void onFailure(int reason) {
                        Toast.makeText(getApplicationContext(),"Not Connected",Toast.LENGTH_SHORT).show();
                    }
                });
            }
        });

        btnSend.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String msg = writeMsg.getText().toString();
                Toast.makeText(getApplicationContext(),"MSG: " + msg,Toast.LENGTH_SHORT).show();
                sendReceive.write(msg.getBytes());
            }
        });
    }

    private void initialWork() {
        btnOnOff= findViewById(R.id.onOff);
        btnDiscover = findViewById(R.id.discover);
        btnSend = findViewById(R.id.sendButton);
        listView = findViewById(R.id.peerListView);
        read_msg_box = findViewById(R.id.readMsg);
        connectionStatus = findViewById(R.id.connectionStatus);
        writeMsg = findViewById(R.id.writeMsg);

        wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);

        mManager = (WifiP2pManager) getSystemService(Context.WIFI_P2P_SERVICE);
        mChannel = mManager.initialize(this, getMainLooper(),null);

        mReceiver = new WiFiDirectBroadcastReceiver(mManager, mChannel, this);

        mIntentFilter = new IntentFilter();
        mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION);
        mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION);
        mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION);
        mIntentFilter.addAction(WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION);
    }



    WifiP2pManager.PeerListListener peerListListener = new WifiP2pManager.PeerListListener() {
        @Override
        public void onPeersAvailable(WifiP2pDeviceList peerList) {
                if(!peerList.getDeviceList().equals(peers)){
                    peers.clear();
                    peers.addAll(peerList.getDeviceList());

                    deviceNameArray = new String[peerList.getDeviceList().size()];
                    deviceArray = new WifiP2pDevice[peerList.getDeviceList().size()];
                    int index = 0;

                    for(WifiP2pDevice device : peerList.getDeviceList()){
                        deviceNameArray[index] = device.deviceAddress;
                        deviceArray[index] = device;
                        index++;
                    }

                    ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(),android.R.layout.simple_list_item_1,deviceNameArray);
                    listView.setAdapter(adapter);
                }

                if(peers.size()==0){
                    Toast.makeText(getApplicationContext(), "No Devices Found",Toast.LENGTH_SHORT).show();
                }
        }
    };



    WifiP2pManager.ConnectionInfoListener connectionInfoListener = new WifiP2pManager.ConnectionInfoListener() {
        @Override
        public void onConnectionInfoAvailable(WifiP2pInfo wifiP2pInfo) {
            final InetAddress groupOwnerAddress = wifiP2pInfo.groupOwnerAddress;

            if(wifiP2pInfo.groupFormed && wifiP2pInfo.isGroupOwner){
                connectionStatus.setText("Host");
                serverClass=new ServerClass();
                serverClass.start();
            }else if(wifiP2pInfo.groupFormed){
                connectionStatus.setText("Client");
                clientClass = new ClientClass(groupOwnerAddress);
                clientClass.start();
            }
        }
    };

    @Override
    protected void onResume() {
        super.onResume();
        registerReceiver(mReceiver,mIntentFilter);
    }

    @Override
    protected void onPause() {
        super.onPause();
        registerReceiver(mReceiver,mIntentFilter);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        try {
            clientClass.socket.close();
            serverClass.serverSocket.close();
            serverClass.socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    @Override
    protected void finalize() throws Throwable {
        super.finalize();
        try {
            clientClass.socket.close();
            serverClass.serverSocket.close();
            serverClass.socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    public class ServerClass extends Thread{
        Socket socket;
        ServerSocket serverSocket;

        @Override
        public void run() {
          //  serverSocket= null;
          //  socket = null;
            try {
                Log.i("ServerSocket is called", "Called");
                serverSocket = new ServerSocket(8888);
                socket = serverSocket.accept();
                sendReceive = new SendReceive(socket);
                sendReceive.start();
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }

    private class SendReceive extends Thread{
        private Socket socket;
        private InputStream inputStream;
        private OutputStream outputStream;

        public SendReceive(Socket skt){
            socket = skt;
            try {
                inputStream = socket.getInputStream();
                outputStream = socket.getOutputStream();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void run() {
            byte[] buffer = new byte[1024];
            int bytes;

            while(socket!=null){
                try {
                    bytes = inputStream.read(buffer);
                    if(bytes > 0){
                        handler.obtainMessage(MESSAGE_READ,bytes,-1,buffer).sendToTarget();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        public void write (byte[] bytes){
            try {
                outputStream.write(bytes);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public class ClientClass extends Thread{
        Socket socket;
        String hostAdd;

        public ClientClass(InetAddress hostAddress){
            hostAdd = hostAddress.getHostAddress();
           // socket = null;
            socket = new Socket();
        }

        @Override
        public void run() {
            try {
                socket.connect(new InetSocketAddress(hostAdd,8888),500);
                sendReceive = new SendReceive(socket);
                sendReceive.start();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

这是我的BroadcastReceiver类：

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.net.NetworkInfo;
import android.net.wifi.WifiManager;
import android.net.wifi.p2p.WifiP2pManager;
import android.nfc.Tag;
import android.util.Log;
import android.widget.Toast;

import static android.content.ContentValues.TAG;

public class WiFiDirectBroadcastReceiver extends BroadcastReceiver {
    private WifiP2pManager mManager;
    private WifiP2pManager.Channel mChannel;
    private MainActivity mActivity;

    public WiFiDirectBroadcastReceiver(WifiP2pManager mManager, WifiP2pManager.Channel mChannel, MainActivity mActivity)
    {
        this.mManager = mManager;
        this.mChannel = mChannel;
        this.mActivity = mActivity;
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if(WifiP2pManager.WIFI_P2P_STATE_CHANGED_ACTION.equals(action)){
            int state = intent.getIntExtra(WifiP2pManager.EXTRA_WIFI_STATE,-1);

            if(state==WifiP2pManager.WIFI_P2P_STATE_ENABLED){
                Toast.makeText(context,"Wifi is ON",Toast.LENGTH_SHORT).show();
            }else {
                Toast.makeText(context,"Wifi is OFF",Toast.LENGTH_SHORT).show();
            }

        }else if(WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION.equals(action)){

            if(mManager!=null){
                mManager.requestPeers(mChannel,mActivity.peerListListener);
            }
            Log.d(TAG, "onReceive: P2P peers changed");
        }else if(WifiP2pManager.WIFI_P2P_CONNECTION_CHANGED_ACTION.equals(action)){
            if(mManager==null){
                return;
            }
            NetworkInfo networkInfo = intent.getParcelableExtra(WifiP2pManager.EXTRA_NETWORK_INFO);
            if(networkInfo.isConnected()){
                mManager.requestConnectionInfo(mChannel,mActivity.connectionInfoListener);
            }else{
                mActivity.connectionStatus.setText("Device Disconnected");
            }

        }else if(WifiP2pManager.WIFI_P2P_THIS_DEVICE_CHANGED_ACTION.equals(action)){
            //do something
        }

    }
}